I've been utilizing the Xbox One for about 6 hours non-stop, and thought some might like an additional perspective.
Set up was easy. It consists of plugging in power, plugging in hdmi, plugging in Kinect, plugging in ethernet(i'm wired). There is an immediate update. From start to finish, it took about 7 or 8 minutes. I somehow managed to dislodge my power strip mid-download the first time around, and the XB1 got a little wonky, but recovered after a reboot. You get walked through setup, which consists of setting the time zone, and logging into xbl, etc. Very quick, no problems for me.
Once you get in: everything is an app and almost nothing is preloaded, so the first time you do just about anything, you have to load an app for it. About the first 2 hours was spent screwing around navigating and downloading apps. We didn't buy any games with the console, so we didn't jump right into a game. Actually, I have Killer Instinct downloaded, but haven't played it yet.
Before I forget, some words on the hardware. In everything I've seen, the console looks enormous. In person it is about the same size as the original Xbox and 360. It's a tiny bit bigger. It looks nice though, like it would really blend in with other components. (I don't have any). The controller is clean, a little better design than the last, not a huge improvement. My only complaint is that it's a little narrow at the shoulder buttons, and I find them more difficult to press than is necessary. It feels a little more cramped than the 360 controller because of this. Let me note that I'm used to large controllers. I still think the original Xbox controller is the best as far as ergonomics go.
However, if I had a choice, I wouldn't use the controller at all. I bought the new system specifically for the Kinect. First things first, out of the box, the Kinect functions suck. Either you have to get used to it, or it has to get used to you, but only now after about 6 hours or screwing around with voice functions, is it really starting to respond well. There's nothing cooler than walking into the room, telling it to turn on, it saying hi, saying a couple of sentences, and you're into whatever you were interested in without ever picking up the controller. That said, the current setup has it's problems. I'll use Xbox Fitness as an example. This is a Kinect app, BUT the menu doesn't support voice commands, so you HAVE TO use the controller with it. Dumb, because you have to put the controller back down to do the exercise. You run into instances like this, where you're cruising along with voice commands, and then all the sudden it's time for controller search. I really want to not use the controller at all for this thing. Another gripe is that the Xbox stops "listening" to commands too quickly, so you end up saying "Xbox select" a lot. This was a really problem at first, since the stupid thing didn't understand half of what I said, but it's much better now. It seems like occasionally when it's busy with another notification, it doesn't listen so well, so the voice commands have to be a bit measured, and after a while you learn to give it a second and speak to it Overall, the controller is probably still much faster. However, consider the scenario where the controller is in between the couch cushions. Now you can turn the console on and get into you app or game while you're looking for the controller. So it's about 90% there with the voice controls, and hopefully that extra 10% is coming with the next update.
The camera works great so far. It took a number of tries, but it now accurately identifies both my wife and I separately and together. Just a funny example of this in action was when I was watching a movie, and she came in from another room and sat down. Xbox said Hi to her, even though it was dark. It's just a cool touch. It's really scary accurate. Xbox Fitness can see what muscles you're utilizing. I got frustrated with it once while calibrating Kinect, and flipped it off. I could tell that the camera saw fingers independent of my hand.
The UI in general is like Windows 8, you just have squares for your applications. Everything is divided up into three sections(pins, home, store), only one of which is fully on screen at once. Frankly I'm not the biggest fan. It would better if "home" was just a single, stationary set of tiles. There's a glitch with voice where occasionally the same command is on screen more than once, and it adds an extra annoying step("xbox select store" "item 1"), or phonetically the commands are too similar, and they end up getting confused. A good example is "pins" and "friends"(xbox select pins" "item 2"). Hand controls are clunky. By the time you get your hand up, recognized, grab, and swipe, you probably could have gotten there with voice, and definitely with the controller. I haven't done it a lot, but I find hand selecting somewhat difficult. The command is put hand up, push forward, pull back. Sounds simple, but it's easy to move your hand while pushing and pulling, either opening the wrong thing, or simply doing nothing.
So far I've downloaded a bunch of apps, "played" Xbox fitness(good free app), surfed the internet(voice is surprisingly good at identifying links. would be nice it could take dictation), watched a Blu-ray disc, and right now my wife is watching Youtube while she cleans the living room.(another handy example of voice control). With a little refinement, this could be GREAT. It needs more, better games(yes, I know they're coming), and it needs better, deeper Kinect control along with more controller-independent apps and games. I think in a year or so, once this comes to fruition, this will be a really great console.